- Off-Highway Truck/Tractor
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Introduction
Revision | Summary of Changes in SEBF8443 |
17 | Updated some illustrations. |
16 | Moved part number to different table. |
15 | Added multiple part numbers. |
© 2015 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law.
Information contained in this document is considered Caterpillar: Confidential Yellow.
This Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.
For questions or additional information concerning this guideline, submit a form for feedback in the Service Information System. To address an urgent issue, use the following resources to communicate your request to Caterpillar Repair Process Engineering:
- Caterpillar Dealer Technical Communicator
- Dealer Solution Network
- Caterpillar Technical Representative
- Knowledge Network
Canceled Part Numbers and Replaced Part Numbers
This document may include canceled part numbers and replaced part numbers. Use NPR on SIS for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.
Important Safety Information
Illustration 1 | g02139237 |
Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure that it is safe for you and for other people to use. Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.
Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information. |
Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.
The hazards are identified by the safety alert symbol which is followed by a signal word such as danger, warning, or caution. The “WARNING” safety alert symbol is shown below.
Illustration 2 | g00008666 |
This safety alert symbol means:
Pay attention!
Become alert!
Your safety is involved.
The message that appears under the safety alert symbol explains the hazard.
Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.
Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.
The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.
Summary
This guideline provides procedures to evaluate the front wheels and the rear wheels of off-highway trucks for reusability. This guideline also includes information for salvaging the bearing bores of the wheel. This guideline includes information for salvaging bolt holes or stud holes in the mounting flanges. Specifications are provided for both the front wheels and the rear wheels. In certain severe conditions, it may be possible for an off-highway truck to develop cracks in the rear wheels. Cracking may occur in the wrapper band or between the two hubs. This guideline provides the information that is required to repair fabricated rear wheels and cast rear wheels. The success of repairing the wheel depends on the extent of the required repair, repair methods, and repair quality. Sometimes, the wheel may not be repairable.
This guideline contains the latest standards of engineering that will help minimize owning and operating costs. Parts that meet the specifications in this guideline can be expected to give normal performance until the next scheduled overhaul when the parts are used in the same application. Never install a part that does not meet the specifications in this guideline. During reconditioning, correct any condition that might have caused the original failure.
Note: Illustrations in this guideline may appear different from some of the components. Although the illustrations are typical, the dimensions are actual.
Service Letters and Technical Information Bulletins
NOTICE |
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The most recent Service Letters and Technical Information Bulletins that are related to this component shall be reviewed before beginning work. Often service advisories and service letters contain upgrades in repair procedures, parts, and safety information that pertain to the parts or components being repaired. |
References
References |
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Reuse and Salvage Guidelines SEBF8187 "Standardized Parts Marking Procedures" |
Reuse and Salvage Guidelines SEBF8882 "Using Lock-N-Stitch Procedures for Casting Repair" |
Reuse and Salvage Guidelines, SEBF9236, "Fundamentals of HVOF Spray Reconditioning Components" |
Reuse and Salvage Guidelines, SEBF9238, "Fundamentals of Arc Spray Reconditioning Components" |
Reuse and Salvage Guidelines, SEBF9240, "Fundamentals of Flame Spray Reconditioning Components" |
Tooling and Equipment
Note: This list tooling is a recommended list. The repair procedure can also be completed if you use tooling that has equivalent capabilities.
Required tooling and Equipment | ||
Part Number | Description | Qty |
Metal Marking Pen | 1 | |
Eye Loupe | 1 | |
Crack Detection Kit | 1 | |
UV Light Kit | 1 | |
Penetrant | 1 | |
Developer | 1 | |
Respirator | 1 | |
Die Grinder (RIGHT ANGLE) |
1 | |
De-burring Grinder | 1 | |
Shaft, Threaded | 1 | |
Disc Pad Holder | 1 | |
Discs (Coarse) | (1) | |
Flapper Wheel (2" x 1" 120 grit) |
(1) | |
Flapper Wheel (2" x 1" 60 grit) |
(1) | |
Micrometer, External |
1 | |
Micrometer Tool Set, External |
1 | |
Micrometer Extensions, Internal |
1 | |
Full Torque Thread Insert Kit | 1 | |
Full Torque Thread Insert Kit | 1 | |
Full Torque Thread Insert Kit | 1 | |
Full Torque Thread Insert Kit | 1 |
(1) | As needed |
Preparation Recommendations
Personal injury can result when using cleaner solvents. To help prevent personal injury, follow the instructions and warnings on the cleaner solvent container before using. |
Illustration 3 | g03721203 |
Typical burr removal tooling. (A) Die Grinder, Right Angle (B) Wheel Grinder Group (C) ( D) ( E) Conditioning Discs, Disc pad Holder, and Threaded Shaft (F) ( G) Flapper Wheels |
- Before you inspect a part, clean the part thoroughly to ensure that all components are free from rust, oil, burrs, and debris prior to inspection. A surface irregularity can hide the indication of an unacceptable defect.
- Use a proper lifting device to provide safety to the operator. Also, use a proper lifting device to prevent damage to the part when you lift the part.
- During cleaning, do not damage machined surfaces.
- Use pressurized air to dry parts.
- Put hydraulic oil on all machined surfaces to prevent rust or corrosion if inspection is not done immediately after cleaning. Carefully store the parts in a clean container.
- Inspect all flange mating surfaces and ensure that flange mating surfaces are true and free from raised material resulting from rust, nicks, and dents.
- Use appropriate thread taps to chase all threaded holes.
Standardized Parts Marking Procedure
Reference: Refer to Reuse And Salvage Guideline, SEBF8187, "Standardized Parts Marking Procedures" for additional information regarding marking procedures.
The code is a Cat standard and is used to record the history of a component. The code will identify the number of repairs and hours at the time of each rebuild. This information is important for any decision to reuse the component.
The mark should not be covered by a mating part. Use a Metal Marking Pen to mark the code onto the component.
NOTICE |
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Do not use a numbering stamp punches set to mark internal parts. The impact from striking the stamp will cause an abnormal stress riser. The added stress riser may cause the part to fail prematurely. |
Illustration 4 | g03695335 |
The procedure for marking the components is a Cat standard. This code is helpful when the machine is sold into a different territory after the first repair. During an overhaul, the previous code of a part should never be removed.
Example 1
Illustration 5 | g03748255 |
Illustration 5 shows code (1-15). The first number (1) indicates that the component had been repaired once. The second number (15) indicates that there were 15,000 hours on the component at the time of repair.
Example 2
Illustration 6 | g03756576 |
Illustration 6 shows code (1-12) and code (2-10). Code (2-10) represents the information from the second repair. The first number (2) indicates that the component had been repaired twice. The second number (10) indicates that 10,000 hours accumulated on the component between the first and second repair.
Note: To obtain the total number of hours for the component in Illustration 6, add first and second repair hours. In this example the component has a total of 22,000 hours.
Rear Wheel
Illustration 7 | g03751003 |
Typical example of rear steel wheel. |
Illustration 8 | g02540156 |
Rear fabricated steel wheel. |
Illustration 9 | g03751116 |
Typical example of rear ductile iron wheel. |
Front Wheel
Illustration 10 | g03751438 |
Typical example of steel casting front wheel. |
Illustration 11 | g03751476 |
Cross section of a steel casting front wheel. |
Illustration 12 | g03751377 |
Typical example of ductile iron front wheel. |
Note: Refer to Table 5 to identify the type of material for the front wheel.
Cleaning Before Inspection
A wheel should be clean before you inspect the wheel. These surfaces must be free of rust, grease, oil, burrs, and paint prior to inspection. This may require the wheel to be blasted with sand to remove any rust and scale. The surfaces for salvage must be free of irregularities. Irregularities may cover up indicators which would make the surface unacceptable to be reused. If the wheel is going to be stored after inspection, put a thin layer of oil on the wheel and make sure that the storage area is clean and dry. Once the wheel has passed the inspection for reusability or the wheel has been salvaged, the wheel needs to be cleaned and painted before the wheel is put back in service.
Illustration 13 | g03755303 |
Features for inspection on front wheels. (1) Seal Surface (2) Seal Surface (3) Inner Bore (4) Splines (5) Outer Bearing Bore (6) Bolt holes (7) Hub (8) Wheel Well (9) Flange |
Rear Wheels
Illustration 14 | g02540357 |
Features for inspection on rear wheels (1) Welds for the wrapper band (2) Weld for the ring (3) Splines (4) Inner bearing bore (5) Seal surface (6) Inner radius of the flange for the rim and stud holes (7) Bolt holes (8) Inner weld for the hub |
General Guidelines
Wheels must be inspected prior to any repair procedure. The wheel should be inspected immediately after disassembly and cleaning. The following list is the critical features of the wheel that must be inspected:
Entire Wheel - Inspect the entire wheel for cracks. Use a Crack Detection Kit (MAGNETIC PARTICLE) for inspection. Inspecting the wheel for cracks is used to identify wheels that are acceptable to be reused. This inspection prevents failure due to existing cracks after the wheel is salvaged. Carefully inspect all radii of the flange for cracks. Inspect all welds for cracks on fabricated wheels.
Splines - The splines are subject to high loads and the splines require inspection. Measure the inside or outside diameter over pins to determine wear. Splines arenot ableto be salvaged. Refer to the "Inspecting the Splines" section of this guideline.
Bearing Bores - Bearing bores may be salvaged by using flame spray or arc spray. Refer to the "Thermal Spray For Bearing Journals" section of this guideline for more information.
Bore for the Duo-Cone Seal Gp - The seal bore may experience damage to the surface that may destroy the integrity of the seal. The seal bore is not to be salvaged.
Mounting Flange Holes - These holes may experience damage if bolts are loose during operation. Inspect the mounting flange holes for deformation. Refer to the "Machining and Dimensions" section of this guideline for machining dimensions for the mounting flange holes and the"Salvage of Bolt and Stud Holes" for the repair procedure.
Threaded Bolt Holes - Threaded bolt holes may be salvaged by using Lock-N-Stitch Full-Torque Threaded Inserts. Refer to the "Full Torque Thread Insert Kits" section of this guideline for the procedure to repair the bolt holes and refer to Reuse and Salvage Guidelines, SEBF8882, "Using Lock-N-Stitch Procedures for Casting Repair" for more information on Lock-N-Stitch products.
Stud Holes - Stud holes that are damaged may be enlarged to accept oversize studs. Refer to the Table 35 for a list of oversize studs and "Weld Repair of Bolt or Stud Holes" section of this guideline for more information.
Bearing Bores of the Wheel
Bearing bores of the wheel can be visually inspected with the naked eye. For the best results during inspection, use a lens that magnifies objects and a strong light source. Use the 8S-2257 Eye Loupe As to inspect the details. Distinguishing between small scratches and small cracks may be difficult. In these cases, use a Crack Detection Kit (MAGNETIC PARTICLE).
Illustration 15 | g03756256 |
Typical section view of bearing bores for rear wheels |
Illustration 16 | g03755421 |
Typical section view of bearing bores for front wheels. |
Measure the diameter of the bores to determine whether the bores meet the criteria. The reuse information for dimensions and tolerances are shown in Table 4 and Table 5.
Reuse Information for Dimensions of Bearing Bores for Rear Wheels | ||||
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Part Number | A | B | Surface Texture (Ra) | Material |
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Ductile Iron Casting | |
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Ductile Iron Casting | |
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Fabricated Steel | ||
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Fabricated Steel | |
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Fabricated Steel | |||
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Fabricated Steel | |
Ductile Iron Casting | ||||
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Fabricated Steel | |
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Fabricated Steel | |
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Steel Casting | |
Ductile Iron Casting | ||||
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Fabricated Steel | |
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Fabricated Steel | |
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Steel Casting | |
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Fabricated Steel | |
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Fabricated Steel | |
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Steel Casting | |
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Fabricated Steel | |
Steel Casting | ||||
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|
Ductile Iron Casting |
Dimensions for Reusability for Bearing Bores on Front Wheels | ||||
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Part Number | A | B | Surface Texture (Ra) | Material |
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Ductile iron casting | |
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Ductile iron casting | |
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Steel casting | |
Ductile iron casting | ||||
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Steel casting | |
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Steel casting | |
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Steel casting | |
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Steel casting | ||
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Steel casting | |
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Ductile iron casting | |
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Steel casting | ||
Inspecting the Splines
Final drive splines are subject to high loads. This makes accurate inspection essential. Splines should be inspected immediately after removal and cleaning. If you are not able to inspect the splines immediately, put hydraulic oil on each machined surface to prevent rust or corrosion.
Visual Inspection
Splines can be visually inspected with the naked eye. To provide the best results from inspection, a lens for magnification and a strong light source are recommended. It can also be difficult to distinguish between small scratches and small cracks. In these cases, use 263-7184 Crack Detection Kit or Liquid Penetrant Examination. Wheels with cracked splines must not be used again. Be sure to inspect every spline on each spindle. If a damaged spline is found, all the splines that mate to the damaged spline and all the splines that are 180 degrees from the damaged spline should be carefully reinspected for possible fatigue from bending. Always use the proper lifting devices for the safety of the operator and to prevent machined damage to the surface. Safety glasses should be worn always for the operator's protection.
Failure Progression
The key element to analyzing damage on final drive splines is determining if the damage will progress to a failure before the next overhaul. Analyze the truck's application and spline size when you are making this determination.
There are two typical failure progressions:
- Spline wear or fracture due to misalignment
- Cracking from fatigue due to fracture
Wear Misalignment
Spline wear is the result of relative motion between mating spline teeth. High loading, insufficient lube, vibration, and abrasive materials are a few of the causes. Typically, splines can be reused if the wear step is less than
There is normally a small amount of relative motion between mating spline teeth. Uneven contact patterns on the spline teeth are the result of misalignment of one or both of the mating splines. If the teeth of the spline are misaligned, the teeth of the spline are not engaged to the full extent of the teeth. This means that only a portion of each tooth is carrying the full load. Misalignment of teeth causes high contact pressures on the portion of the tooth that is carrying the load. Thus, damage to the surface that is associated with high contact pressures and relative movement will be seen as wear on the spline and corrosion due to fretting. Misalignment can be identified by the uneven contact pattern on the spline teeth.
Worn bearings, damaged bearings, worn spindles, or damaged spindles can cause misalignment. If any spline displays uneven contact patterns, be sure to check for misalignment and correct the problem. Splines with wear due to misalignment do not prevent you from reusing the wheel, if the highest area of wear does not exceed the reuse criteria of the spline.
Fatigue Cracks
Numerous broken teeth of the spline are the result of a failure due to fatigue from bending. The operational loads create tensile stress in the area of the fillet on the loaded side of the tooth. With enough high loads and cycles, these stresses can cause cracks due to fatigue. After a crack due to fatigue develops, the crack will continue to progress until the tooth is sufficiently weakened and the crack separates from the parent metal. Cracking can also occur between the root of the tooth and a bolt hole or inside diameter of the part.
Examples of Reusability of Splines
Illustration 17 | g01238172 |
Use a seal pick to check the splines. |
Push the seal pick from the worn area to the worn area. Measure the splines if the splines have a wear step that is large enough to stop the seal pick. Refer to the "Measuring Procedures to Evaluate the Limits of Wear on the Spline". Generally, a
Illustration 18 | g03756338 |
When possible, use a steel straight edge and a feeler gauge to measure questionable splines. Refer to the "Measuring Procedures to Evaluate the Limits of Wear on the Spline" section of this guideline. |
Illustration 19 | g01238200 |
The heavy wear step in this illustration stopped a seal pick. The spline is being measured with a feeler gauge to determine reusability because of the stopped seal pick. The depth of the wear step is greater than |
Do not use the spline again.
Remember to check the ends of the engagement of the splines. Use a seal pick as a go, no-go, gauge. If the splines are not worn evenly, check for problems from alignment and measure the splines prior to reusing the splines.
Illustration 20 | g03756360 |
The seal pick stopped at the engagement point of the spline. Do not use the spline again. |
Normal Wear
Illustration 21 | g01240327 |
This internal spline has normal wear. The wear pattern is even due to full contact during operation. |
Use the spline again.
Illustration 22 | g01240340 |
This spline shows signs of even loading and full contact. |
Use the spline again.
Illustration 23 | g01240355 |
Use one of the Crack Detection Kits that is specified in Table 3 to check the part for cracks. This spline has a deep indentation but this spline does not show any signs of cracking. Use a stone for polishing to smooth any sharp edges around the indentation. |
Use the spline again.
Illustration 24 | g01240365 |
This spline has an external wear step. This spline is acceptable for reusability because the dimensions meet the reuse criteria that is shown in Table 6. There is corrosion due to fretting from the lack of lubrication. Alone, the fretting does not prohibit the reusability of this spline. |
Damage on Teeth
Illustration 25 | g01240374 |
A tooth of the spline is missing and the adjacent teeth of the spline are heavily damaged. |
Do not use the spline again.
Illustration 26 | g01240382 |
A spline has developed a crack in the area of the root. The crack has progressed into the adjacent splines. |
Pitting and Fretting
Illustration 27 | g01240390 |
The heavy pitting (arrow) will progress into spalling. Eventually, the tooth will fracture and the tooth will look like the missing tooth that is shown in Illustration 25. |
Do not use the spline again.
Illustration 28 | g01240661 |
Heavy fretting due to corrosion on this spline will eventually cause the spline to spall the teeth. |
Measuring Procedures to Evaluate the Limits of Wear on the Spline
Illustration 29 | g01240665 |
Typical wear step on an external spline |
Illustration 30 | g01240668 |
Typical wear step on an internal spline |
To insure adequate life of the components, this document contains highly precise tolerances for measurements taken on various features. Therefore, good practice is to insure several sample measurements are taken at different locations on the same feature. For this procedure, each type of spline will require the use of a specific pin set. Each pin is ground to a specific dimension. Care must be taken to precisely machine these pins to the specification due to the close tolerances of the splines. Make the pins out of SAE1020 steel. Use the dimension for the pin diameter in Table 4 to precisely machine each pin for the specific pin set. Magnetize each pin so that the pins will stay in place during the process of measurement.
Tools used for measuring should include outside diameter micrometer for motor spline. These tools must measure to four decimal places in inch units or three decimal places in mm units. Measuring tools should be calibrated using gauge blocks certified to a national standard such as the National Institute of Standards and Technology (NIST).
To obtain accurate results, you must have a thorough working knowledge of the use of micrometers. Calculate the average for the three measurements over pins. Use the following procedure to determine the maximum allowable spline wear.
Use the following procedure to determine the maximum allowable spline wear.
- Determine the wear on each spline by using an inside or an outside micrometer. To obtain accurate results, the individual person that is performing the check must understand the use of both inside micrometers and outside micrometers.
- Place pins on the spline at intervals of 60 degrees. Secure the pins in place. If the pins are magnetized the pins should stay in place.
Show/hide table
Illustration 31 g01240681 Place pins at 60 degree intervals. The pins should be magnetized or the pins should be retained by a rubber band to prevent movement. Show/hide tableIllustration 32 g01240682 Internal measurements of the spline with pins at 60 degree intervals.
Take measurements between pins that are located 180 degrees across from each other.Show/hide tableIllustration 33 g01240690 External measurement of the spline with pins at 60 degree intervals.
Take measurements over pins that are located 180 degrees across from each other.Show/hide tableIllustration 34 g01240718 The outside micrometer must be positioned to measure the highest two points of the pins. - The micrometer must be positioned to measure the highest external two points or the internal two points on the pins. This will provide the reading of wear for the spline. The pin diameter for each individual part is specified in Table 6. Take a measurement over pins at 60 degree intervals. Add the readings together and divide the sum by three. The maximum reading over pins or minimum reading over pins must also be determined because the out of round measurement will cause poor load distribution on the spline teeth.
Example of Measurements for Internal Splines
Place pins at 60 degree intervals on the component. The location of the pins at 60 degree intervals is critical to the formula. These three locations will provide information on the wear of the part. Make sure that the pins that are used for the measurement are 180 degrees across from each other.
Illustration 35 | g01240725 |
Measure the diameter at locations (A), (B), and (C). |
Step 1 through Step 4 demonstrates the calculations that are necessary to check the measurements of an internal spline at 60 degree intervals. The numbers that are given are only for example. The specifications that are used in this example are for a 8X-1047 Wheel. Refer to Table 6 for specifications.
- Measure the diameter at locations (A), (B), and (C).
- Add the diameters together.
- Divide the result by 3 to obtain the average.
If the calculated dimension is less than the Specification for Reusability Over Pins in Table 6, then the part passes this requirement.
- The difference between the high measurement and the low measurement gives an indication if the splines are out of round. If the splines are out of round the splines may experience an uneven load distribution. Take the high measurement and the low measurement and calculate the difference. The difference between the two measurements also determines if the wheel can be used again.
Table 6 designates a Maximum Difference Between the High Measurement and the Low Measurement. If the actual difference is less than the allowable maximum, then the spline can be used again.
If the actual difference between the High Measurement and the Low Measurement exceeded the Maximum Difference, then the splined component would be elliptical and the component could not be used again.
Note: Both the Specification for Reusability Over Pins and the Maximum Difference Between the High Measurement and the Low Measurement must be within the specifications that are given. If the part does not meet both specifications, do not reuse the part.
Example of Measurements for External Splines
Place pins at 60 degree intervals on the component. The location of the pins at 60 degree intervals is critical to the formula. These three locations will provide information about the wear of the part.
Illustration 36 | g01240768 |
Measure the diameter at locations (A), (B), and (C). |
Step 1 through Step 4 demonstrates the calculations that are necessary to check the measurements of an external spline at 60 degree intervals. The numbers that are given are only for example. The specifications that are used in this example are for a 119-9065 Wheel. Refer to Table 6 for specifications.
- Measure the diameter at locations (A), (B), and (C).
- Add the diameters together.
- Divide the result by 3 to obtain the average.
If the calculated dimension is less than the Specification for Reusability Over Pins in Table 6, then the part passes this requirement.
If the calculated dimension is greater than the Specification for Reusability Over Pins in Table 6, then the part passes this requirement.
- The difference between the high measurement and the low measurement gives an indication if the splines are out of round. If the splines are out of round the splines may experience an uneven load distribution. Take the high measurement and the low measurement and calculate the difference. The difference between the two measurements also determines if the wheel can be used again.
Table 6 designates a Maximum Difference Between the High Measurement and the Low Measurement. If the actual difference is more than the allowable maximum, then the spline is elliptical and the spline should not be used again.
Note: Both the Specification for Reusability Over Pins and the Maximum Difference Between the High Measurement and the Low Measurement must be within the specifications that are given. If the part does not meet both specifications, do not reuse the part.
Data for the Reusability of the Spline
Data for the Reusability of the Spline | ||||||
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Part Number | Type | Pressure Angle | Gage Pin Diameter | Specification Over Pins | Specification for Reusability Over Pins (1) | Maximum Difference Between the High Measurement and the Low Measurement |
Internal | 30° | |
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Internal | 30° | |
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External | 14.5° | |
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- | - | |
External | 30° | |
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External | 14.5° | |
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Internal | 14.5° | |
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Internal | 20° | |
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- | - | |
Internal | 14.5° | |
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External | 30° | |
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- | - | |
Internal | 30° | |
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External | 14.5° | |
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- | - | |
External | 20° | |
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- | - | |
External | 30° | |
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- | - |
(1) | Minimum for external splines, Maximum for internal splines |
Thermal Spray For Bearing Journals
NOTICE |
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Do NOT proceed with the wheel repair procedure if cracks appear in the bearing bores or the splines. |
Flame Spray and Arc Spray are both acceptable operations for repairing bearing bore surfaces in wheels.
The Special Instruction, SEBF9236, "Fundamentals of HVOF Spray for Reconditioning Components"Special Instruction, SEBF9238, "Fundamentals of Arc Spray for Reconditioning Components", Special Instruction, SEBF9240, "Fundamentals of Flame Spray for Reconditioning Components", provides recommendations for applications for various parts that use Flame, Arc, or HVOF spray.
Welding Specifications and Qualifications
Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can kill. Read and understand the manufacturer's instruction and your employer's safety practices. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing zone and the general area. Wear correct eye, ear and body protection. Do not touch live electric parts. Refer to the American National Standard Z49.1, "Safety in Welding and Cutting" published by the American Welding Society, 2501 N.W. 7th Street, Miami, Florida 33125: OSHA Safety and Health Standards, 29 CFR 1910, available from U.S. Dept. of Labor, Washington D.C. 20210. |
Note: Personal breathing protection should be worn by the personnel that are welding. Personal breathing protection will prevent fumes from entering the lungs of the person that is welding. Use a 237-5181 Respirator for breathing protection.
Qualifications
Welders must be qualified for the appropriate type of weld that is being performed. Welders must be qualified for the appropriate position of weld that is being performed. Welders must be qualified for the welding process that is being utilized: Shielded Metal Arc Welding (SMAW) and Flux Cored Arc Welding (FCAW). Refer to Specification ANSI/AWS D1.1 for information that regards qualification requirements. The welders must have used the process at some time within the last 6 months. The welders must complete the process of certification if the welders have not used the welding processes for 6 months.
General Information on Welding Repair
In certain severe conditions, it may be possible for an off-highway truck to develop cracks in the rear wheel assemblies. Cracking may occur in the area of the wrapper band or between the two hubs.
This guideline provides the necessary information to repair fabricated wheels and cast wheels. Successfully repairing the wheel depends on the extent of the required repair, repair methods, and repair quality. Sometimes, repairing the wheel may not be possible.
Off Highway Trucks may be equipped with a fabricated wheel that is made of three pieces, a fabricated wheel that is made out of two pieces, or a cast wheel. Repair procedures in this publication are defined for fabricated wheels and cast wheels. Since fabricated wheels require a repair procedure that is different from cast wheels, it is important to know the differences between the two types of wheels. Refer to the following illustrations to identify fabricated wheels and cast wheels.
The serial numbers of the individual rear wheels should be recorded. The following information should also be recorded:
- Repair date
- Type of repair
- Name of the welder
Note: The repair procedure for fabricated wheels is different from the repair procedure for cast wheels.
Illustration 37 | g01242971 |
Types of wheels (A) Fabricated wheel that is made of three pieces (B) Fabricated wheel that is made of two pieces (C) Cast wheel |
Note: Refer to Special Instruction, SEBF9236, "Fundamentals of HVOF Spray for Reconditioning Components"Special Instruction, SEBF9238, "Fundamentals of Arc Spray for Reconditioning Components", Special Instruction, SEBF9240, "Fundamentals of Flame Spray for Reconditioning Components", for more information on welding.
Information on the Fixture for the Wheel
Prior to any repair by welding, the fabricated wheels must be mounted securely in a fixture for welding to hold dimensions and tolerances.
Note: Fixtures are intended only for fabricated wheels. Fixtures may be used for cast wheels, but the fixtures may require some modification.
A fixture can be constructed to support the wheel assembly. The following Tables and Illustrations provide the proper dimensions for construction. The completed fixture should be used with a positioner that is capable of supporting
Note: Before attaching the ground cable of the welder to the base of the positioner, check the specifications of the manufacturer to make sure that the machine is designed to allow the cable to be attached at the base. If the machine is not designed to allow the cable to be attached at the base, attach the ground cable directly to the wheel. The current from welding will destroy the bearings if the current is allowed to flow through the bearings.
Illustration 38 | g03756416 |
Fixture Assembly Refer to Table 7 for identification of the callouts. |
Bill of Materials | ||
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Item | Quantity | Description |
1 | 1 | 1020 HR Plate |
2 | 8 | 1020 HR Plate |
3(1) | 1 | Seamless Welded Drawn Over Mandrel Tubing |
3(2) | 1 | Seamless Welded Drawn Over Mandrel Tubing |
4 | 1 | 1020 HR Plate |
5 | 1 | 1020 HR Plate |
6 | 3 | Rod with six Threads The Model determines the length. |
7 | 2 | 6061 T6 Aluminum Plate for Bearing Bores |
8 | 6 | |
9 | 6 | Nuts with six Threads |
(1) | 785, 785B, 789, 789B, 789C, 789D, 793, 793B, 793C, 793D, 793F |
(2) | 773, 773B, 773D, 773G, 777, 777B, 777D, 777G |
Illustration 39 | g01243059 |
Pedestal of the Fixture Refer to Table 7 and 8 for identification of the callouts. (M) Eight (N) Eight (P) Four (1/2 - 13 THD) (Q) Plug for welding into the tube (R) 45° Bevel Groove weld with a |
Dimensions for the Pedestal of the Fixture | ||
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Item | 785, 785B, 789, 789B, 789C, 789D, 793, 793B, 793C, 793D, 793F | 773, 773B, 773D, 773G, 777, 777B, 777C, 777D, 777G |
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(1) | 785 and 785B wheels |
(2) | 789, 789B, 793, and 793B, 793C, 793D, 793F wheels |
Illustration 40 | g01245301 |
Plate for the fixture Refer to Table 9 for the specifications of the callouts. (S) Three (T) Four (1/ 2 inch - 13 THD) (U) (V) |
Dimensions for the Fixture for the Plate of the Bearing Bore | ||||||
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Part Number | (An Inner) Bore | (An Outer) Bore | B | C | D | E |
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Process for Welding and Consumables for Fabricated Wheels
Caterpillar recommends using Flux Cored Arc Welding (FCAW).
NOTICE |
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Use the recommended parameters of the electrode supplier. If the electrode supplier does not give recommended parameters, use the following parameters. |
FCAW Process for Welding and Consumables | |||
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Process for Welding | Type of Electrode | Diameter | Specification from American Welding Society (AWS) |
FCAW | Dual Shield II 70 | |
E71T-1 |
FCAW | Dual Shield 7000 | |
E71T-1 |
FCAW | Dual Shield 7100 | |
E71T-1 |
Parameters for Welding from the FCAW(1) | ||||
Consumable | Wire Feed Speed | Amperes | Volts | Polarity |
DS 7000 FCAW | |
275 | 28 | Reverse |
DS II 70 FCAW | |
275 | 28 | Reverse |
DS 7100 FCAW | |
275 | 28 | Reverse |
(1) | Use a shielding gas of carbon dioxide or 75% Argon and 25% carbon dioxide at |
Required Parts
(1) | Three-piece fabricated wheel |
(2) | Two-piece fabricated wheel with |
(3) | Two-piece fabricated wheel with |
Procedure to Remove the Wrapper Band
- Remove all oil, grease, paint, dirt, and other material from the area. Remove surface oxides within a minimum of
25 mm (1 inch) from either side of the welding area. - Protect all machined areas from sparks and spatter that is produced by carbon cutting, welding, and grinding processes.
- Use the carbon cutting process to remove the existing wrapper band. Make shallow cuts to prevent destroying the geometry of the existing weld joint. You will eliminate the cast backup at the rests of the wrapper band if the weld is too deep. You will then need to use material for welding to build up a cast backup.
Note: The welds may be machined to remove the wrapper band if a lathe is available and the lathe has the capacity to support a wheel assembly. This will reduce the chances for distortion versus using the carbon cutting process.
- The metal edges must be dressed with a grinder and the metal edges must be dressed with a rotary file that is equipped with a carbide cutter after you remove the wrapper band. This will eliminate any carbon or rough edges that affect the integrity of the weld.
Note: The rotary file is used to remove any abrasive particles that may have been embedded in the surface by the grinder. This prevents contamination of the weld bead.
- Inspect the inner circumferential weld of the hub. If a crack is present, use the carbon cutting process to remove the crack. Take care not to cut through the hub. Use the rotary file to clean up the area and remove any carbon or rough edges.
- Preheat the weld groove and the surrounding area to at least
93 °C (200 °F) .Note: The temperature for the rest of the wheel should be at least
21 °C (70 °F) before welding the wheel. This temperature should be maintained while the wheel is welded. - Follow the "Process for Welding and Consumables for Fabricated Wheels" section of this guideline for the correct parameters for welding for the inner circumferential weld of the hub.
- After completing the repair, allow the wheel to cool slowly to
21 °C (70 °F) .
Locations for the Wrapper Band, Block, and Lug
Machining Dimensions for Hubs with Thicker Wrapper Band | |||||||
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Wheel | Hubs | Original Diameter | Machined Diameter (K) | Angle (L) | Radius | Machined Dimension (O) | Mounting Flange (P) |
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N/A | N/A |
(1) | Wrapper bands are |
(2) | Wrapper bands are |
Illustration 41 | g01247864 |
(D) Hub
(K) Machined diameter for 785 and 785B with (K) Machined diameter for |
Illustration 42 | g01249925 |
(D) Hub
(K) Machined diameter for 793 and 793B with (L) Reference angle (M) Reference radius |
Illustration 43 | g01249934 |
773, 773B, 773D, 773E, 777, 777B, 777C, and 777D fabricated wheel assembly. (A) See Table 14. (L) (M) (V) |
Location for the Wrapper Band, Block, and Lug | |||||
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Procedure for the Wrapper Band, Block, and Lug
NOTICE |
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Do NOT proceed with the wheel repair procedure if cracks appear in the bearing bores or the splines. |
- Remove all oil, grease, paint, dirt, and other material from the area. Remove surface oxides that are within
25 mm (1 inch) of either side of the area for welding. - Preheat the weld groove and the surrounding area to at least
93 °C (200 °F) .Note: The temperature for the rest of the wheel should be at least
21 °C (70 °F) before welding and during welding. This temperature is required to avoid thermal shock and this temperature should not be confused with the requirements for preheating for welding. The piece should be protected from drafts. Pay special attention to protecting the piece in cold weather. - Attach the appropriate wrapper bands to the wheel assembly. Check the position of the bands in relation to the centerline of the wheel.
Show/hide table
Illustration 44 g01250026 - Weld the wheel by using the specifications from the callouts.
(N) Weld from Point (A) to Point (B).
Note: 2 places
(P)
8.0 mm (0.24 inch) V-groove weld with a4.0 mm (0.16 inch) penetrationNote: 2 places
(Q-Q) All fabricated wheels
(R-R) 785 and 785B wheel assembly
- Weld the seams of the wrapper band. Weld from one end to the other end without stopping. After the seam of the wrapper band welds are finished, complete the circumferential welds.
- Weld the wrapper bands into the place. Do not start or stop the weld within the area from point (C) to point (D).
Show/hide table
Illustration 45 g01288959 785 and 785B welds for the block and lug.
(S)6.0 mm (0.24 inch) fillet weld on ten blocks
(T)6.0 mm (0.24 inch) fillet weld on both sides of ten blocks
(U)10.0 mm (0.39 inch) fillet weld on each sideShow/hide tableIllustration 46 g01288960 Welds for 789, 789B, 793, and 793B blocks.
(S)6.0 mm (0.24 inch) fillet weld on ten blocks
(T)6.0 mm (0.24 inch) fillet weld on each side of four lugs
(W)6.0 mm (0.24 inch) fillet weld on each side of two blocks
(X) Use a4.0 mm (0.16 inch) square groove weld under a12.0 mm (0.47 inch) V-groove weld for the 789 and 789B. Weld in two places.
(X) Use a4.0 mm (0.16 inch) square groove weld under a16.0 mm (0.63 inch) V-groove weld for the 793 and 793B. Weld in two places.Show/hide tableIllustration 47 g01250099 Dimensions of the lug. - Attach the appropriate blocks and lugs into position. For the 785, 789, 793, and 793B models refer to Illustration 45 through Illustration 47 and Table 14 for the proper position.
Show/hide table
Illustration 48 g01250133 (A) Weld location for the inner diameter of the hub. - Allow the wheel assembly to cool slowly to room temperature. Remove the wheel from the fixture. Check the inner diameter of the hub for the required weld. If the situation is applicable, weld the inner diameter of the hub by using an
11.0 mm (0.43 inch) weld with1.5 mm (0.06 inch) penetration all around. Organize the weld around the circumference to control distortion.Note: This weld was formerly used in the production of fabricated wheels and the weld may be required to repair earlier fabricated wheels.
- Allow the wheel assembly to cool, and then check the dimensions of the wheel assembly.
- Check the weld quality during the entire repair procedure. Weld areas must be free from cracks, porosity, undercut, and incomplete fusion. Weld quality must conform to AWS D1.1 or D14.3 specifications.
Procedure to Weld Cracks that Go from Ring to Hub in Fabricated Wheels
Note: This section excludes the 6G-3658 Wheel for the 777.
If any cracks are detected in the welds that join the ring to the hub, complete the following procedure.
Illustration 49 | g01250198 |
(B) Ring
(C) Wrapper band (D) Hub |
NOTICE |
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Do NOT proceed with the wheel repair procedure if cracks appear in the bearing bores or the splines. |
- Remove all oil, grease, paint, dirt, and other material from the area. Remove surface oxides within
25 mm (1 inch) of either side of the area for welding. - Locate crack (A) on the inside of the wheel assembly.
Show/hide table
Illustration 50 g01250214 (A) Crack
(B) Ring
(D) Hub
(E) V-groove - Form a
6.0 mm (0.24 inch) to8.0 mm (0.32 inch) V-groove (E) by using the carbon cutting process. Use a rotary file to dress the groove. Use a rotary file to provide a 60° opening.Show/hide tableIllustration 51 g01250231 (B) Ring
(D) Hub
(F) Outside weld groove
(G) Inside repair weld
(H) Original weld - Preheat the weld groove and the surrounding area to at least
93 °C (200 °F) .Note: The temperature for the rest of the wheel should be at least
21 °C (70 °F) before welding and during welding. This temperature is required to avoid thermal shock and this temperature should not be confused with the requirements for preheating for welding. The piece should be protected from drafts. Pay special attention to protecting the piece in cold weather. - Weld the inside of the case of the wheel and leave a contour from the weld bead that blends gradually between the section of the metal that is thicker and the section of the wheel that is thinner.
- Form the outside weld groove (F) to a depth that removes the entire defect. Use the rotary file to remove slag and oxidized metal. Use the rotary file to provide a 60° opening.
- Before you weld, the crack must be removed. Use Magnetic particle inspection to ensure that the crack has been removed.
Show/hide table
Illustration 52 g01252536 - Weld the outside groove to produce a contour with a gradual transition from the cross section that is thicker to the cross section that is thinner.
- After completing the repair, allow the wheel to cool slowly to
21 °C (70 °F) .
The construction of the 6G-3658 Wheel does not have wrapper bands. Cracks can be prepared by using the procedure in the "Procedure to Weld Cracks that Go from Ring to Hub in Fabricated Wheels" section of this guideline. The wheels should be mounted in a fixture during the repair. Allow the wheel to cool slowly to room temperature after the repair process. Then remove the wheel from the fixture.
Check the inner diameter of the hub for the required weld. Refer to the "Procedure for the Wrapper Band, Block, and Lug" section of this guideline and Step 8 through Step 10 and Illustration 48 for the procedure.
The Procedure to Replace Rings on 785 and 789 Fabricated Wheels
Repair Process and Consumables for Welding the Ring
NOTICE |
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Use the recommended parameters of the electrode supplier. If no recommended parameters are stated, use the following. |
Caterpillar recommends using:
- Flux Cored Arc Welding
Process and Consumables for Flux Cored Arc Welding | |||
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Process for Welding | Type of Electrode | Diameter | Specifications for AWS |
FCAW | Dual Shield II 70 | |
E71T-1 |
FCAW | Dual Shield 7000 | |
E71T-1 |
FCAW | Dual Shield 7100 | |
E71T-1 |
Parameters for FCAW(1) | ||||
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Consumable | Wire Feed Speed | Amperes | Volts | Polarity |
DS 7000 FCAW | |
275 | 28 | Reverse |
DS II 70 FCAW | |
275 | 28 | Reverse |
DS 7100 FCAW | |
275 | 28 | Reverse |
(1) | Use a shielding gas of carbon dioxide or 75% Argon and 25% carbon dioxide at |
Procedure to Remove the Ring
- Remove all oil, grease, paint, dirt, and other material from the area.
- Remove the surface oxides within
25 mm (1.0 inch) of both sides of the weld area. - Protect all the machined areas from sparks or spatter that is produced by the carbon cutting, welding, and the process for grinding.
- Remove the old ring from the hub.
Note: A vertical lathe or a vertical mill is the preferred method for removing the old ring from the hub. This will reduce the chances of distortion when the old ring is removed. If a lathe is not available, use the carbon cutting process to remove the existing ring from the hub. Make shallow cuts to prevent destroying the geometry of the existing weld joint.
Note: Control distortion by arranging the cutting and the welding. This is important because distortion will affect the bearing bore and the dimensions of the flange.
Procedure to Prepare
Illustration 53 | g01252696 |
Inner section of the hub. |
Dimensions for Preparing the Hub | ||
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Part Number | Dimension | Dimension |
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- Complete the preparation of the joint of the weld on the hub surface. Refer to Illustration 53 and Table 17 for the specifications.
Note: If the carbon cutting process was used to remove the ring, the area around the joint of the hub must be dressed with a grinder. Then use a rotary file that is equipped with a carbide cutter. This will eliminate any carbon or rough edges, which affect the integrity of the weld.
Note: The rotary file is used to remove any abrasive particles that were embedded in the surface by the grinder. This prevents contamination of the weld bead.
Welding Procedure
- Place the wheel on the fixture for welding. Refer to the "Information on the Fixture for the Wheel" section of this guideline for more information.
Show/hide table
Illustration 54 g01252795 - Install the new ring on the prepared hub.
Show/hide table
Table 18 Dimensions for Preparing the Hub Part Number A B 5T-9539 (1)1053.00 ± 0.5 mm
(41.45661 ± 0.01968 inch) - 5T-5842 ,(1)8W-9929 (1)1194.7 ± 0.5 mm
(47.03534 ± 0.01968 inch) - 8X-2633 (2)1053.00 ± 0.5 mm
(41.45661 ± 0.01968 inch) 1047.00 ± 0.3 mm
(41.22039 ± 0.01181 inch) 8X-2636 (2)1194.7 ± 0.5 mm
(47.03534 ± 0.01968 inch) 1188.70 ± 0.3 mm
(46.79912 ± 0.01181 inch) Show/hide table(1) Design of taperlock stud with no step (2) Design of press in stud with antirotation step Note: Use a dial indicator to make sure that the ring is concentric with the bearing bore of the wheel. Locate the ring according to the dimensions in Illustration 54 and Table 18. Be sure that the rough ring of the flange is spaced to leave enough stock to finish the flange on both sides. Refer to the "Dimensions for Fabricated Wheels" section of this guideline.
- Preheat the weld groove and the surrounding area to at least
93 °C (200 °F) .Note: The temperature for the rest of the wheel should be at least
21 °C (70 °F) before welding and during welding. This temperature is required to avoid thermal shock and this temperature should not be confused with the requirements for preheating for welding. The piece should be protected from drafts. Pay special attention to protecting the piece in cold weather. - Tack weld the ring in eight places on both sides of the ring. Alternate sides and place the tack welds so that the tack welds are spread apart by 180° to avoid any distortion.
Note: Use an AWS E71S-1 solid wire Gas Metal Arc Welding GMAW consumable and AWS E71S-1 solid wire Gas Metal Arc Welding GMAW process for tack welding and root passes on the procedure to replace the ring.
- Make sure that there is full penetration on the root pass on the inside and outside welds.
- Alternate passes of the circumferential welds from inside to outside to reduce the chances of distortion.
Show/hide table
Illustration 55 g01252536 Cross section of weld joint from the ring to the hub.
(B) Ring
(D) Hub
(J) Repair weld - The finished welds should have the complete penetration and the profile that is shown in Illustration 55.
- Allow the wheel to cool slowly to
21 °C (70 °F) .
Note: Check the weld quality during the entire repair procedure. Weld areas must be free from cracks, porosity, undercut, and incomplete fusion. Weld quality must conform to AWS D1.1 or D14.3 specifications.
Machining Procedure
- Install the wheel on the vertical mill or the lathe.
- Center the wheel off the bearing bores.
Show/hide table
Illustration 56 g01142415 (F) Refer to the "Repair Procedure For Inner Rear Wheel Mounting Flange" section and the "Machining and Dimensions" section of this guideline for hole diameters and locations. - Machine the inner flange on the ring to the dimensions in Table 19.
Show/hide table
Table 19 Dimensions for Preparing the Hub Part Number Dimension Dimension 5T-9539 (1)A 1007.00 mm
(39.64559 inch) B 1050.00 ± 0.5 mm
(41.33850 ± 0.01968 inch) C (R) 3.00 ± 0.5 mm
(0.11811 ± 0.01968 inch) D - E 0.03 mm
(0.00118 inch) by 45 degrees5T-5842 (1)8W-9929 (1)A 1148.70 ± 0.5 mm
(45.22432 ± 0.01968 inch) B 1191.70 ± 0.5 mm
(46.91723 ± 0.01968 inch) C (R) 3.0 ± 0.5 mm
(0.11811 ± 0.01968 inch) D - E - 8X-2633 (2)A 1007.00 ± 0.25 mm
(39.64559 ± 0.00984 inch) B 1047.00 ± 0.25 mm
(41.22039 ± 0.00984 inch) C (R) 3.0 ± 0.5 mm
(0.11811 ± 0.01968 inch) D 1.6 ± 0.4 mm
(0.06299 ± 0.01575 inch) E 0.03 mm
(0.00118 inch) by 45 degrees8X-2636 (2)A 1148.70 ± 0.5 mm
(45.22432 ± 0.01968 inch) B 1188.70 ± 0.25 mm
(46.79912 ± 0.00984 inch) C (R) 3.0 ± 0.5 mm
(0.11811 ± 0.01968 inch) D 1.6 ± 0.4 mm
(0.06299 ± 0.01575 inch) E - Show/hide table(1) Design for Taperlock stud with no step (2) Design for press in stud with antirotation step Note: Be sure that the proper radii are machined on the top and bottom of the flange. This is required to remove any sharp corners that could act as stress risers.
- Drill the stud holes in the ring to the sizes that are listed in the "Repair Procedure For Inner Rear Wheel Mounting Flange" section of this guideline and the "Machining and Dimensions" section of this guideline for hole diameters and locations.
Note: Be sure that the proper chamfer is machined on each stud hole if the chamfer is required.
Inspection and Cleanup Procedure
- Check the dimensions of the wheel assembly. All dimensions must be within the specified tolerance.
- Clean the entire wheel.
- Paint all the surfaces that have been repaired. Do not paint any of the machined surfaces that were not originally painted.
Dimensions for Fabricated Wheels
The following tables and illustrations provide the important dimensions for inspecting the wheels during the repair and the wheels after the repair. The dimensions are listed below:
(A) Bearing bore diameter
(B) Bearing bore diameter
(C) Distance between the bottom of the bearing bores
(D) Distance between the mounting face of the carrier and the mounting face of the wheel
Note: When welding is complete, measure dimension (D) to determine the shrinkage of the face of the carrier. You may need to add material or you may need to remove material to conform with the dimensions that are given.
(E) Diameter of the seal groove
(F) Diameter of stud stop.
(G) Distance between the bottom of the bearing bore to the face of the spline end.
(H) Bottom of the bearing bore to the carrier
(I) Depth of the bearing bore
(J) Depth of the bearing bore
Note: All radii must be a minimum of
Illustration 57 | g01252859 |
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Illustration 58 | g03239579 |
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Illustration 59 | g01256986 |
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Illustration 60 | g01256994 |
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Illustration 61 | g01257024 |
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Illustration 62 | g01257037 |
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Illustration 63 | g01257060 |
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Illustration 64 | g01257114 |
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Dimensions for Fabricated Wheels | |||||
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Dimensions of Fabricated Wheels | |||||
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Part Number | F | G | H | I | J |
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Process and Consumables for Welding Cast Steel Wheels
Part Numbers of Rear Cast Steel Wheels |
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Part Number |
Process and Consumables for Welding | |||
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Process for Welding | Type of Electrode | Diameter | Specification for AWS |
FCAW | Dual Shield 2 100D1 | |
E100T1-G |
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Parameters for Welding(1) | ||||
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Diameter of Consumables | Wire Feed Speed | Amperes | Volts | Polarity |
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275 | 28 | Reverse |
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275 | 28 | Reverse |
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275 | 28 | Reverse |
(1) | Use a shielding gas of Carbon Dioxide or 75% Argon and 25% Carbon Dioxide at |
NOTICE |
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Do NOT proceed with the wheel repair procedure if cracks appear in the bearing bores or the splines. |
- Before attaching the ground cable of the welder to the base of the positioner, check the specifications of the manufacturer to make sure that the machine is designed to allow the cable to be attached at the base. If the machine is not designed to allow the cable to be attached at the base, attach the ground cable directly to the wheel. The current from welding will destroy the bearings if the current is allowed to flow through the bearings. Do NOT allow the welding current to travel through bearings or hydraulic cylinders. Protect all hydraulic cylinders, struts, hoses, and machined surfaces from sparks and spatter that is produced by the welding, chipping, and grinding operations.
- Locate any cracks and remove any cracks that were caused by carbon gouging or grinding. Gouge the crack or grind the crack to the bottom of the crack. Gouge the crack or grind the crack to a minimum of
18.0 mm (0.7 inch) past each end of the crack. Use a rotary file to dress the area and remove any carbon or rough edges. Remove all slag or spatter and clean the joint of the repair. Use magnetic particle inspection in adequate light to verify that all cracks have been removed.Note: Machining is an alternate method for removing cracks. Machine only the minimum amount of material that is necessary to ensure the total removal of the crack.
- Preheat the weld groove and the surrounding area to at least
93 °C (200 °F) .Note: The temperature for the rest of the wheel should be at least
21 °C (70 °F) before welding. - Repair the weld joint by using stringer welds. Remove the slag after each pass to avoid possible slag inclusions. The size of the weld pass should not exceed a width of
8 mm (0.32 inch) .Note: An alternate welding process is using a E10018-D2 stick electrode. Keep the size of the weld pass to less than two times the diameter of the electrode. An acceptable alternative welding wire is Tri-Mark TM1-05D2 Flux Cored Wire.
- Allow the wheel assembly to cool slowly to room temperature after the process for welding. Then check the dimensions of the wheel assembly. All dimensions must be within the specified tolerance prior to the final assembly.
- Check the quality of the weld during the entire repair process. The areas of repair of the wheel must be free from cracks, porosity, undercut, and incomplete fusion. Weld quality must conform to AWS D1.1 or D14.3 qualifications.
Dimension For Cast Steel Wheels
The following tables and illustrations provide the important dimensions for inspecting the wheels during repair and following repair.
Note: All radii must be a minimum of
Illustration 65 | g01258455 |
Cast Wheel |
Dimensions for Cast Steel Wheels | |||||
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Dimensions for Cast Steel Wheels | |||||
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Dimensions for Ductile Iron Wheels
The following tables and illustrations provide the important dimensions for inspecting the ductile iron wheels.
Illustration 66 | g01258557 |
795F, 797 Wheel |
Illustration 67 | g01258573 |
773, 773B, 773D, 775B, 775D, and 775E Wheel |
Illustration 68 | g01258581 |
769, 769B, 769C, 769D, 771C, and 771D Wheel |
Dimensions for Ductile Cast Iron Wheels | |||||
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Dimensions for Ductile Cast Iron Wheels | |||||
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(1) | Minimum dimension |
Salvage of Bolt and Stud Holes
Repair Procedure For Outer Rear Wheel Mounting Flange
Illustration 69 | g01042620 |
Example of a Full-Torque threaded Insert |
The bolt holes on the outer mounting flange of the rear wheel can be salvaged with Full-Torque threaded Inserts. Full-Torque threaded Inserts use unique external threads. These inserts will contain the force that spreads of the fastener. These inserts will only transfer a radial force that draws the surrounding material. Full-Torque threaded Inserts can be used on ductile iron wheels and steel wheels.
Full Torque Thread Insert Kits
Refer to the following tables for the appropriate Kits. 784B, 784C, 785, 785B, 785C, 789, 789B, and 789C bolt holes can be repaired by using the 263-7140 Full Torque Thread Insert Kit (1 inch thread) that can be found in Table 29. 793 through 793C bolt holes can be repaired by using the 263-7141 Full-Torque Thread Insert Kit (M24 Thread) that can be found in Table 30.
For more information or questions concerning LOCK-N-STITCH, see www.locknstitch.com for repair procedures, training, and catalogs.
LOCK-N-STITCH Inc.1015 S. Soderquist Rd.
Turlock, CA 95380
(209) 632-2345
(800) 736-8261
Fax (209) 632-1740
263-7140 Full Torque Thread Insert Kit (1 inch thread)(1) | |
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Part Number | Description |
Roughing Tap (24 mm Thread) | |
Finishing Tap (24 mm Thread) | |
Threaded Insert (1 inch Thread) | |
Insert Installation Tool (1 inch Thread) | |
Drill Bit (Size 9, 1 9/64 inch) | |
Fluid (Tapping) | |
Sealant |
(1) | This kit is designed for ductile iron wheels on Off Highway Trucks and Wheel Loaders. This kit can be used on steel fabricated wheels and cast wheels. |
263-7141 Full-Torque Thread Insert Kit (M24 Thread)(1) | |
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Part Number | Description |
Roughing Tap (24 mm Thread) | |
Finishing Tap (24 mm Thread) | |
Threaded Insert (M24 Thread) | |
Insert Installation Tool (M24 Thread) | |
Drill Bit (Size 9, 1 9/64 inch) | |
Fluid (Tapping) | |
Sealant |
(1) | This Kit is designed for ductile iron wheels on Off Highway Trucks and Wheel Loaders. This kit can be used on steel fabricated wheels and cast wheels. |
Thread Sizes for the Outer Flange on the Rear Wheel | ||
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Part Number | Diameter | Thread Size |
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3/4-10-2B | |
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3/4-10-2B | |
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1-8-2B | |
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1-8-2B | |
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M24 × 3-6H |
Procedure to Repair 797 and 797B Extension Housings
Note: Inspect the Final Drive Housing for cracks. Do not salvage the housing if cracks exist.
The following information is given to repair bolt holes on 139-7623 Final Drive Housings for the 797 and 797B by using the 263-7142 Full-Torque Thread Insert Kit (M30 Thread) that can be found in Table 32. The
Illustration 70 | g01125573 |
(1) Repair by using the (2) Repair by using the |
263-7142 Full-Torque Thread Insert Kit (M30 Thread)(1) | |
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Part Number | Description |
Roughing Tap (Size 11) | |
Finishing Tap (Size 11) | |
Threaded Insert (M30 Thread) | |
Insert Installation Tool (M30 Thread) | |
Threaded Insert (1 25/64 inch Thread) | |
Bit Holder (for FT10-13 Inserts) | |
Fluid (Tapping) | |
Sealant |
(1) | This kit is designed for the ductile iron extension housings on 797 Off-Highway Trucks. |
263-7144 Full-Torque Thread Insert Kit (M36 Thread)(1) | |
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Part Number | Description |
Roughing Tap (Size 13) | |
Finishing Tap (Size 13) | |
Threaded Insert (M36 Thread) | |
Insert Installation Tool (M36 Thread) | |
Threaded Insert (1 41/64 inch Thread) | |
Bit Holder (for FT10-13 Inserts) | |
Fluid (Tapping) | |
Sealant |
(1) | This kit is designed for the ductile iron extension housings on 797 Off-Highway Trucks. This kit can also be used for repairing mounting holes for the steering bracket on the 797 front axle. |
Repair Procedure For Inner Rear Wheel Mounting Flange
- Use an applicable ring for the wheel or construct a template to determine the axis of the damaged hole. Refer to the "Machining and Dimensions" section of this guideline for the specifications and the locations of the holes.
- Refer to Table 34 for the applicable hole size. If necessary, order the applicable replacement stud. Refer to Table 35.
- Fill the damaged hole by welding. Refer to the following section "Weld Repair of Bolt or Stud Holes".
- Machine both sides of the flange before drilling.
- Maintain the original axis and drill the hole to the original specifications by using a standard drill. If oversize replacement studs are used, drill the hole to the appropriate size. Refer to Table 35.
Note: If the wheel has taperlock studs, refer to Table 34 for the proper information on drilling holes and tapping holes for taperlock studs.
Note: Some wheels require a chamfer on the holes on the back side of the flange. Refer to Table 34 for more information.
Show/hide tableTable 34 Thread or Hole Sizes for Inner Rear Wheel Mounting Flange Part Number Diameter Thread Size 2G-5003 ,8D-4934 16.75 mm
(0.65945 inch) - 6G-3658 ,6G-6563 16.75 mm
(0.65945 inch) - 5T-9539 22.50 mm
(0.88583 inch) 1-8-2B 8X-2633 ,139-9584 22.50 mm
(0.88583 inch) - (2) 5T-5842 ,8W-9929 22.50 mm
(0.88583 inch) 1-8-2B (1) 8X-2636 ,125-0061 ,142-5946 27.04 mm
(1.06456 inch) - (2) 8X-1019 ,102-0313 ,125-5937 ,132-4515 ,135-2555 27.04 mm
(1.06456 inch) - (2) Show/hide table(1) This is a hole for a taperlock stud. Drill through the hole with a drill that has a 22.5 mm (0.89 inch) diameter. Tap the hole with the 1-8-2B tap. The hole should have a depth of29.46 ± 1.27 (1.160 ± 0.050 inch) . The tap should have a lead angle of 12 degrees and 30 minutes ± 1 degree.(2) The hole requires a chamfer of 2.0 mm (0.08 inch) by 45 degrees on the back side of the flange.
Information about Optional Replacement Studs
Replacement Information for Wheel Studs | |
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Wheel Stud from Production | Replacement Wheel Stud |
Weld Repair of Bolt or Stud Holes
Note: Repairing bolt holes and stud holes by using welding can only be done on steel cast wheels or on steel fabricated wheels. No welding should be performed on ductile iron wheels.
Inspection
The wheel must be inspected before any welding procedure is performed. An inspection for cracks must be performed to prevent failure of the wheel after the salvage operation. Remove any corrosion that covers up unacceptable defects. The acceptable inspection methods are the dye penetrant and the magnetic particle inspection.
Process and Consumables
Caterpillar recommends using:
- Gas Metal Arc Welding
- AWS A5.5-69 E10018-D2 Electrode
Preparation and Welding
- Remove all oil, grease, paint, dirt, and other material from the area. Remove surface oxides within a minimum of
25 mm (1 inch) on either side of the welding area. - Protect all machined areas from sparks or spatter that is produced by carbon cutting, welding, and grinding.
- The temperature of the wheel should be at least
21 °C (70 °F) before any cutting or welding. - Drill an oversized hole at the location of the damaged hole. Chamfer the top of the hole. Make sure that all the old threads are removed. Make sure that any corrosion that was in the bottom of the hole is removed.
- Preheat the area that surrounds the hole to at least
93 °C (200 °F) . - Make sure that no voids or gaps are left in the hole that might weaken the structure when you are welding.
- Allow the welded hole to cool slowly to room temperature. After the surface has reached room temperature, machine the surface so that the surface is flush with the rest of the flange.
- Refer to Table 31, Table 34, or Table 35 for the proper specifications for finishing the proper hole in the wheel.
Note: If the wheel has Taperlock studs, refer to Table 34 for the proper information on drilling and tapping a hole for a Taperlock stud.
- After machining the new hole, the wheel needs to be cleaned and repainted to avoid corrosion.
Machining and Dimensions
Dimensions are provided for the proper locations of the holes. Most of the hole locations are located from the center of the wheel.
A CNC machine can be used for locating the true position of the holes. A template could be used to locate the holes.
The following sections are divided by truck models. The sections provide the dimensions that are necessary to drill the holes.
Dimensions for Front Wheels of 769B, 769C, 769D, and 770G
Illustration 71 | g00698304 |
Location of the holes for the front wheels of the 769B, 769C, 769D, and 770G |
Dimensions for Front Wheels |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
Hole Diameter | |
Dimensions for Rear Wheels of 769B, 769C, 769D, and 770G
Illustration 72 | g00698342 |
Location of the holes for the rear wheels of the 769B, 769C, 769D, and 770G |
Dimensions for Rear Wheel |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
Hole Diameter | |
Dimensions for Front Wheels of the 772, 772B, 772G, 773, 773B, 773D, 773E, 775B, 775D, and 775E
Illustration 73 | g00698359 |
Location of the holes for the front wheels of the 772, 772B, 772G, 773, 773B, 773D, 773E, 775B, 775D, and 775E |
Dimensions for |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
M | |
N | |
Hole Diameter | |
Dimensions for Rear Wheels of the 772, 772B, 772G, 773, 773B, 773D, 775E, 775B, 775D, and 775E
Illustration 74 | g00698368 |
Location of the holes for the rear wheels of the 772, 772B, 772G, 773, 773B, 773D, 773E, 775B, 775D, and 775E |
Dimensions for |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
M | |
N | |
Hole Diameter | |
Dimensions for Front Wheels of the 776, 776B, 776C, 776D, 777, 777B, 777C, and 777D
Illustration 75 | g00698392 |
Location of the holes for the front wheels of the 776, 776B, 776C, 776D, 777, 777B, 777C, and 777D |
Dimensions for |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
Hole Diameter | |
Dimensions for Rear Wheels of the 776, 776B, 776C, 776D, 777, 777B, 777C, and 776D
Illustration 76 | g00698403 |
Location of the holes for the rear wheels of the 776, 776B, 776C, 776D, 777, 777B, 777C, and 776D |
Dimensions for |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
M | |
N | |
O | |
P | |
Q | |
R | |
S | |
T | |
Hole Diameter | |
Dimensions for Front Wheels of the 784B, 784C, 785, 785B, and 785C
Illustration 77 | g00698406 |
Location of the holes for the front wheels of the 784B, 784C, 785, 785B, and 785C |
Note: The holes that are damaged may be redrilled to accept the optional replacement studs. Refer to Table 35.
Dimensions for |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
M | |
N | |
O | |
P | |
Q | |
R | |
S | |
T | |
U | |
V | |
Hole Diameter | |
Dimensions for Rear Wheels of the 784B, 784C, 785, 785B, and 785C
Illustration 78 | g00698421 |
Location of the holes for the rear wheels of the 784B, 784C, 785, 785B, and 785C |
Note: The holes that are damaged may be redrilled to accept the optional replacement studs. Refer to Table 35.
Dimensions for |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
M | |
N | |
O | |
P | |
Q | |
R | |
S | |
T | |
U | |
V | |
W | |
X | |
Y | |
Z | |
AA | |
Hole Diameter | |
Dimensions for Front Wheels of the 789, 789B, and 789C
Illustration 79 | g00698442 |
Location of the holes for the front wheels of the 789, 789B, and 789C |
Note: The holes that are damaged may be redrilled to accept the optional replacement studs. Refer to Table 35.
Dimensions for |
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Location | Dimension |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
M | |
N | |
O | |
P | |
Q | |
R | |
S | |
T | |
U | |
V | |
W | |
X | |
Y | |
Z | |
AA | |
Hole Diameter | |
Dimensions for Rear Wheels of the 789, 789B, and 789C
Illustration 80 | g00698452 |
Location of the holes for the rear wheels of the 789, 789B, and 789C |
Note: The holes that are damaged may be redrilled to accept the optional replacement studs. Refer to Table 35.
Dimensions for |
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Location | Diameter |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
M | |
N | |
O | |
P | |
Q | |
R | |
S | |
T | |
U | |
V | |
W | |
X | |
Y | |
Z | |
AA | |
Hole Diameter | |
Dimensions for Front and Rear Wheels of the 793, 793B, and 793C
Illustration 81 | g00698459 |
Location of the holes for the front wheels of the 793, 793B, and 793C |
Note: The holes that are damaged may be redrilled to accept the optional replacement studs. Refer to Table 35.
Dimensions for |
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Location | Dimensions |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
I | |
J | |
K | |
L | |
M | |
N | |
O | |
P | |
Q | |
R | |
S | |
T | |
U | |
V | |
W | |
X | |
Y | |
Z | |
AA | |
BB | |
CC | |
DD | |
EE | |
FF | |
GG | |
HH | |
II | |
JJ | |
KK | |
LL | |
MM | |
NN | |
OO | |
PP | |
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RR | |
SS | |
TT | |
UU | |
VV | |
WW | |
XX | |
YY | |
ZZ | |
AB | |
AC | |
AD | |
AE | |
AF | |
AG | |
AH | |
AJ | |
AK | |
AM | |
AN | |
AO | |
AP | |
AQ | |
AR | |
AS | |
AT | |
AU | |
Hole Diameter | |
Dimensions for Front and Rear Wheels of the 793D, and 793F
Illustration 82 | g03870044 |
Location of the holes for the rear wheels of the 793D, and 793F |
Note: The holes that are damaged may be redrilled to accept the optional replacement studs. Refer to Table 35.
Dimensions for |
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Location | Dimensions |
A | |
B | |
C | |
D | |
E | |
F | |
G | |
H | |
J | |
K | |
L | |
M | |
N | |
P | |
R | |
S | |
T | |
U | |
V | |
W | |
X | |
Y | |
Z | |
AA | |
AB | |
AC | |
AC | |
AD | |
AE | |
AF | |
AG | |
AH | |
AJ | |
AK | |
AL | |
AM | |
AN | |
AP | |
AR | |
AS | |
AT | |
AU | |
AV | |
AW | |
AX | |
AY | |
AZ | |
BA | |
BB | |
BC | |
BD | |
BE | |
BF | |
BG | |
BH | |
BJ | |
BK | |
BL | |
BM | |
BN | |
BP | |
BR | |
BS | |
BT | |
BU | |
BV | |
BW | |
BX | |
BY | |
BZ | |
CA Hole Diameter |
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CB | |
Dimensions for Front and Rear Wheels of 795F and 797
Illustration 83 | g01258993 |
Locations of hole centers for the front wheel, and the large flange of 795F and 797rear wheels. The hole diameter is |
Center locations of holes for |
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Hole | Y-Axis
Vertical |
X-Axis
Horizontal |
A | |
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B | |
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C | |
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D | |
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E | |
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F | |
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G | |
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H | |
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I | |
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J | |
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K | |
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L | |
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M | |
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N | |
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Illustration 84 | g01259022 |
Locations of the hole centers for the small flange of 795F and 797 rear wheels. Hole diameter is |
Center locations of holes for the small flange of |
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Hole | Y-Axis
Vertical |
X-Axis
Horizontal |
A | |
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B | |
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C | |
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D | |
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E | |
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F | |
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G | |
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H | |
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K | |
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L | |
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Crack Detection Methods
NOTICE |
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Regardless of which crack detection method is used, it is important that the instructions furnished with the detection equipment are followed closely when checking any parts. Failure to do so may cause inaccurate results. |
Inspection personnel can reference ASTM E165 and E709 for further details on inspection processes.
Personnel who perform examinations in accordance with this guide shall be qualified and certified. Individuals must be certified for Magnetic Particle Inspection at a minimum Level I in accordance with ASNT Recommended Practice No. SNT-TC-1A or ASNT CP-189.
Crack detection methods commonly used are liquid penetrant, dry magnetic particle, wet magnetic particle, and ultrasonic testing. There may be more than one acceptable crack detection method for the inspection of a given part, although the liquid penetrant is the most versatile. Select the method that best fits your shop's operation. Sometimes, characteristics of a particular part may prevent the use of certain inspection systems.
For example, a liquid penetrant system cannot be used to inspect for subsurface cracks in a steel part. Use Table 50 to determine the best system for the type of structure being inspected. The wet magnetic particle inspection method is best used when inspecting smooth machined components such as shafts, gear teeth, and splines. If the wet magnetic particle inspection method is not available, it can be substituted with the liquid penetrant examination method.
Crack Inspection Method Advantages vs. Disadvantages | ||
---|---|---|
Inspection Method | Advantages | Disadvantages |
Liquid Penetrant | - Least expensive - Minimal training - Portable - Works on nonmagnetic material |
- Least sensitive - Detects surface cracks only |
Dry Magnetic Particle | - Portable - Fast |
- Works on magnetic material only - Less sensitive than Wet Magnetic Particle |
Wet Magnetic Particle | - More sensitive than Liquid Penetrant - Detects subsurface as much as |
- Requires Power for Light - Works on magnetic parts only - Liquid composition and agitation must be monitored |
Ultrasonic Testing | - Most sensitive - Detects deep material defects |
- Most expensive - Requires operator training and certification |
Liquid Penetrant Examination
Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any chemical that is used. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of chemicals. |
Materials and Equipment Required
Refer to Tooling and Equipment Table 3 for part numbers.
- Cleaner: Removes dirt before dye application and dissolves the penetrant making possible to wipe the surface clean.
- Penetrant: This solution is highly visible, and will seep into openings at the surface of a part with capillary action.
- Developer: Provides a blotting action, bringing the penetrant out of the discontinuities and providing a contrasting background to increase the visibility of the penetrant indications.
- Wire Brush: Removes dirt and paint.
- Cloth or Wipes: Use with cleaner and for other miscellaneous uses.
Procedure
Illustration 85 | g03791241 |
- Preclean inspection area. Spray on cleaner to loosen any scale, dirt, or any oil. Wipe the area to inspect with a solvent dampened cloth to remove remaining dirt and allow the area to dry. If there is visible crack remove paint using paint remover or wire brush.
Show/hide table
Illustration 86 g03791250 - Apply penetrant by spraying to the entire area to be examined. Allow 10 to 15 minutes for penetrant to soak. After the penetrant has been allowed to soak, remove the excess penetrant with clean, dry wipe.
Show/hide table
Illustration 87 g03791397 - The last traces of penetrant should be removed with the cleaner solvent dampened cloth or wipe. Allow the area to dry thoroughly.
Show/hide table
Illustration 88 g03791251 - Before using developer make sure that, it is mixed thoroughly by shaking can. Holding can approximately 8-12 inches away from part, apply an even, thin layer of developer over the area being inspected. A few thin layers are a better application method than one thick layer.
Show/hide table
Illustration 89 g03510598 - Allow the developer to dry completely for 10–15 minutes before inspecting for cracks. Defects will show as (A) red lines in white developer background. Clean the area of application of the developer with solvent cleaner.
Dry Magnetic Particle Inspection
Materials and Equipment Required
- Crack Detection Kit
Illustration 90 | g03536204 |
(A) Indications shown by magnetic particle testing.
(B) Typical electromagnetic yoke.
(C) Dry powder bulb.
- Dry magnetic powder shall be of high permeability and low retentively and of suitable sizes and shapes to produce magnetic particle indications. The powder shall be of a color that will provide adequate contrast with the background of the surface being inspected.
- Dry magnetic particles shall be stored in suitable containers to resist contamination such as moisture, grease, oil, non-magnetic particles such as sand, and excessive heat. Contaminants will manifest in the form of particle color change and particle agglomeration. The degree of contamination will determine further use of the powder.
- Dry magnetic powder shall be tested in accordance with ASTM E709 Section 18 (Evaluation of System Performance/Sensitivity) when not performing.
- Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least
4.5 kg (10 lb) . - Check dry powder blower routinely to ensure that the spray is a light, uniform, dust-like coating of the dry magnetic particles. Blower should also have sufficient force to remove excess particles without disturbing those particles that are evidence of indications.
- All equipment shall be inspected at a minimum of once a year or when accuracy is questionable.
Procedure
- Insure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and other contaminants.
- Apply the magnetic field using the yoke against the faces and inside diameter of each bore.
- Simultaneously apply the dry powder using the dry powder blower.
- Remove excess powder by lightly blowing away the dry particles.
- Continue around the entire circumference of each bore. Position the yoke twice in each area at 1.57 rad (90°) to ensure that multiple directions of the magnetic field are created.
- Observe particles and note if any clusters of particles appear revealing an indication.
- Record the size and shape of any discontinuities or indications found.
Wet Magnetic Particle Inspection
Materials and Equipment Required
- Crack Detection Kit
- UV Lamp Light
Illustration 91 | g03536207 |
(A) Indications shown by magnetic particle testing.
(B) Typical electromagnetic yoke.
(D) UV lamp used in wet/liquid magnetic particle inspection process.
- Wet magnetic particles are fluorescent and are suspended in a vehicle in a given concentration that will allow application to the test surface by spraying.
- Concentration:
- The concentration of the suspended magnetic particles shall be as specified by the manufacturer and be checked by settling volume measurements.
Show/hide table
Illustration 92 g03801656 - Concentrations are determined by measuring the settling volume by using an ASTM pear shaped centrifuge tube with a
1 mL (0.034 oz) stem with0.05 mL (0.0017 oz) divisions. Before sampling, the suspension shall be thoroughly mixed to assure suspension of all particles, which could have settled. A100 mL (3.40 oz) sample of the suspension shall be taken and allowed to settle for 30 minutes. The settling volume should be between0.1 mL (0.0034 oz) and0.25 mL (0.0085 oz) in a100 mL (3.40 oz) sample. - Wet magnetic particles may be suspended in a low viscosity oil or conditioned water.
- The oil shall have the following characteristics:
- Low viscosity not to exceed 50 met (5.0 cSt) at any temperature at which the vehicle is to be used.
- Low inherent fluorescence and be non-reactive.
- The conditioning agents used in the conditioned water shall have the following characteristics:
- Impart good wetting characteristics and good dispersion.
- Minimize foaming and be non-corrosive.
- Low viscosity shall not exceed a maximum viscosity of 50 mSt (5.0 cSt) at
38° C (100° F) . - Non-fluorescent, non-reactive, and odorless.
- Alkalinity shall not exceed a pH of 10.5.
- The concentration of the suspended magnetic particles shall be as specified by the manufacturer and be checked by settling volume measurements.
- Equipment should include a "U" shaped electromagnetic yoke made from highly permeable magnetic material, which has a coil wound around the yoke. This coil carries a magnetizing current to impose a localized longitudinal magnetic field into the part. The magnetizing force of the yoke is related to the electromagnetic strength and can be tested by determining the lifting power of a steel plate. The yoke shall have a lifting force of at least
4.5 kg (10 lb) .
Procedure
- Insure surface to be inspected is dry and free from oil, grease, sand, loose rust, mil scale, paint, and any other contaminants.
- Apply the magnetic field using the yoke against the surface in the area to be inspected.
- For case hardened and ground surfaces:
- Sensitivity required to locate the grinding cracks. Inspection of case hardened and ground surfaces require that the yoke is applied so that the magnetic field is 1.57 rad (90°) to the expected direction of the indications. Due to the increased sensitivity resulting while the yoke is energized, the yoke is not moved until the evaluation is completed in the first direction. An AC yoke shall be used.
- Visually inspect for indications of discontinuities using the proper illumination.
- Record the size and shape of any discontinuities found.